1. Field of the Invention
The present invention relates to an electrically conductive material supply apparatus and method for supplying a ball of an electrically conductive material such as solder to a predetermined position to electrically connecting a plurality of electrodes or the like.
2. Related Background Art
For example, a process of manufacturing a magnetic head includes a step of connecting an electrode provided on a so-called magnetic head core and an end of an electrical wire on a so-called gimbal that supports the core. According to a known technique directed to such a process, a ball of an electrically conductive material is supplied to a position near the electrode and the wire end to establish electrical connection therebetween via that ball, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-170351. In this method, a solder ball is used as the electrically conductive material, and in order to separate many balls that are stored together in a portion from each other, use is made of a disk-like member provided with a plurality of through holes that are arranged at a certain distance from the rotation center with regular angular intervals. When the disk-like member is rotated, solder balls get into the through holes and are separated and transferred one by one. The through holes are in communication with ball transfer passages and the balls fall in the transfer passage by their own weight, whereby each ball moves to a predetermined supply position. The ball at that supply position is irradiated with a laser beam to melt, whereby electrical connection is established between the electrode and the wire end. In this method, the transfer passages also serve as passages for supplying nitrogen gas that is supplied to prevent oxidation of solder balls. The nitrogen gas helps transfer of the solder ball to the supply position.
In recent years, the size of magnetic heads has been made smaller and their structure has been made more complex with reduction in the size and improvement in the performance of magnetic recording apparatuses (or hard disk drives (HDD)) in which the magnetic heads are used. The diameter of the solder ball has also been reduced significantly with reduction in the size of the magnetic head, and in the case of the method disclosed in the aforementioned Japanese Patent Application Laid-Open No. 2002-170351 it is difficult to hold the ball at a predetermined position between the electrode and the wire end with reliability. A solution to the above described problem is disclosed in Japanese Patent Application Laid-Open No. 2004-534409. According to the method disclosed in this publication, a holder that stores a solder ball in the interior space provided therein is provided with a small opening for supplying a solder ball, and the solder ball is held on the opening in such a way as to stop the opening. The holder that is holding the solder ball in this way is positioned without being in contact with the electrode, and then the solder ball is melted by laser irradiation while the pressure in the interior of the holder is increased, so that the molten solder ball is ejected from the opening and the molten solder is attached to a prescribed position on the electrode.